Translations on this website are prepared by a third-party provider. Some portions may be incorrect. Some items—including downloadable files or images—cannot be translated at all. No liability is assumed by Beth Israel Deaconess Medical Center for any errors or omissions. Any user who relies on translated content does so at his/her own risk.

BOSTON – A scientific team led by investigators at Beth Israel Deaconess Medical Center (BIDMC) has developed new experimental models to evaluate targeted therapies for the treatment of papillary thyroid carcinoma (PTC). PTC is the most common type of thyroid cancer, and incidence of the disease is increasing worldwide. The team’s findings, published online in the open-access journal Oncotarget, suggest that combination therapy might offer a new therapeutic strategy for metastatic PTC.

“Molecular analysis of this cancer shows that nearly 60 percent of PTC cases contain a mutation called BRAF-V600E,” explained senior author Carmelo Nucera, MD, PhD, an investigator in the Department of Pathology at BIDMC. “This mutation increases the cancer’s ability to metastasize, or spread to other organs.”

Although targeted therapies that inhibit the BRAF mutation have been successful for the short-term treatment of melanoma and other types of cancer, it has been found that the tumors eventually regrow, becoming more aggressive and resistant to drugs.

“The goal of our study was to generate and test experimental models in both PTC cell cultures and in a mouse model to evaluate therapeutic responses of BRAF inhibitors for the treatment of PTC,” said Nucera, who is also Assistant Professor of Pathology at Harvard Medical School and a member of the Cancer Research Institute and the Center for Vascular Biology Research at BIDMC.

Nucera and colleagues developed three models. The first consisted of normal patient-derived thyroid cells; the second was a model of BRAF-V600E mutation in papillary thyroid cells, and was divided into subgroups of PTC with and without metastasis. The third model consisted of PTC cells without BRAF-V600E mutation.

The scientists went on to test selected BRAF-V600E inhibitors in each of the three models and found significant anti-tumor activity in PTC cells with BRAF-V600E mutation with no metastasis. “It seems that metastasis elicits some intrinsic resistance to these inhibitors,” Nucera said.

The scientists next conducted experiments to determine the mechanism underlying the drug resistance. “We screened patient PTC samples, both with and without metastasis,” said Nucera. “We found two mechanisms that were involved in BRAF-V600E-positive PTC with metastasis: the pro-survival factor MCL1 (1q), which is genomically upregulated and the cell cycle inhibitor P16 (9p), which is genomically deregulated.”

Finally, the researchers combined BRAF-V600E inhibitors with pro-survival inhibitors and discovered that combined therapy was more effective than a single agent treatment at overcoming intrinsic resistance in PTC cells. “Our new models suggest that this combination of targeted drugs might be a crucial therapeutic strategy for metastatic and refractory BRAF-V600E positive PTC,” Nucera noted.

This study was supported by grants from the National Cancer Institute (1R21CA165039-01A1, 1R01CA181183-01A1) as well as support from the American Thyroid Association and ThyCa, and the Thyroid Cancer Survivors Association Inc. for Thyroid Research.

About Beth Israel Deaconess Medical Center

Beth Israel Deaconess Medical Center is a patient care, teaching and research affiliate of Harvard Medical School and consistently ranks as a national leader among independent hospitals in National Institutes of Health funding.

BIDMC is in the community with Beth Israel Deaconess Hospital-Milton, Beth Israel Deaconess Hospital-Needham, Beth Israel Deaconess Hospital-Plymouth, Anna Jaques Hospital, Cambridge Health Alliance, Lawrence General Hospital, MetroWest Medical Center, Signature Healthcare, Beth Israel Deaconess HealthCare, Community Care Alliance and Atrius Health. BIDMC is also clinically affiliated with the Joslin Diabetes Center and Hebrew Rehabilitation Center and is a research partner of Dana-Farber/Harvard Cancer Center and the Jackson Laboratory. BIDMC is the official hospital of the Boston Red Sox. For more information, visit www.bidmc.org